Object of this invention is an arrangement for generating a rocking motion of a transfer cylinder of an inking system, particularly for offset printing machines.
The task of a similar arrangement is to provide a transfer cylinder of an inking system, an intermittent motion related to an intermittent motion of the ductor cylinder.
The rotating ductor cylinder collects on its surface printing ink from a storage device and a uniform layer of printing ink is created on its surface by an adjustable doctor blade. The printing ink is taken over by the transfer cylinder and transmitted to the cylinders of the inking system.
Actually known arrangements have the rocking motion of the transfer cylinder derived from the rotating motion of the ductor cylinder, which motion may be either continuous or intermittent. The amount of printing ink taken over by the transfer cylinder is for arrangements with continuous rotating motion of the ductor cylinder dependent on the length of track of the mutual contact of both cylinders. In arrangements with intermittent rotating motion of the ductor cylinder, the amount of ink taken over by the transfer cylinder is controlled by the angular displacement of the ductor cylinder and can be equally adjusted.
In arrangements where the ductor cylinder performs a continuous rotating motion, the rocking motion of the transfer cylinder is obtained by a cam, receiving its drive from the ductor cylinder. This cam is in constant contact with an eccentrically arranged lever controlling the mechanism of the transfer cylinder. The length of track of the mutual rolling contact of the transfer cylinder and the ductor cylinder is adjustable by changing the position of an eccentric bolt of this lever.
A drawback of this arrangement is that at a continuous rotation of the ductor cylinder dirt and dust from the paper are with higher intensity introduced into the ink of the ink storage device, influencing unfavorably the adjustment of thickness of the ink layer on the ductor cylinder.
Other known arrangements where the ductor cylinder performs an intermittent motion are provided with a cam on the driving chain wheel, with a roller, supported rotatably on a two arm lever, contacting this cam. The two arm lever transmits to the transfer cylinder the rocking motion. The length of track of the mutual rolling contact of the transfer cylinder and the ductor cylinder cannot be adjusted in this arrangement. It is only possible to adjust the magnitude of the angular displacement of the ductor cylinder.
A drawback of this arrangement is that the rocking motion of the transfer cylinder is derived from a cam and cannot be adjusted, whereby similar arrangements are complicated.